Since the beginning of photography and cinematography, the most common type of image and video content has been captured and displayed as a two-dimensional (2D) rectangular scene. The main reason of this is that cameras are mainly directional, i.e., they capture only a limited angular field of view (the field of view towards which they are directed).
More recently, new image and video capture devices are available. These devices are able to capture visual and audio content all around them, i.e. they can capture the whole angular field of view, sometimes referred to as 360 degrees field of view. More precisely, they can capture a spherical field of view (i.e., 360 degrees in all axes). Furthermore, new types of output technologies have been invented and produced, such as head-mounted displays. These devices allow a person to see visual content all around him/her, giving a feeling of being “immersed” into the scene captured by the 360 degrees camera. The new capture and display paradigm, where the field of view is spherical, is commonly referred to as virtual reality (VR) and is believed to be the common way people will experience media content in the future.